High-Q CMOS-integrated photonic crystal microcavity devices

Abstract

Integrated optical resonators are necessary or beneficial in realizations of various functions in scaled photonic platforms, including filtering, modulation, and detection in classical communication systems, optical sensing, as well as addressing and control of solid state emitters for quantum technologies. Although photonic crystal (PhC) microresonators can be advantageous to the more commonly used microring devices due to the former's low mode volumes, fabrication of PhC cavities has typically relied on electron-beam lithography, which precludes integration with large-scale and reproducible CMOS fabrication. Here, we demonstrate wavelength-scale polycrystalline silicon (pSi) PhC microresonators with Qs up to 60,000 fabricated within a bulk CMOS process. Quasi-1D resonators in lateral p-i-n structures allow for resonant defect-state photodetection in all-silicon devices, exhibiting voltage-dependent quantum efficiencies in the range of a few 10 s of %, few-GHz bandwidths, and low dark currents, in devices with loaded Qs in the range of 4,300–9,300; one device, for example, exhibited a loaded Q of 4,300, 25% quantum efficiency (corresponding to a responsivity of 0.31 A/W), 3 GHz bandwidth, and 30 nA dark current at a reverse bias of 30 V. This work demonstrates the possibility for practical integration of PhC microresonators with active electro-optic capability into large-scale silicon photonic systems.

Inkjet‐Printed Nanocavities on a Photonic Crystal Template

“…[43,44] One could then envisage using a generic 2D PhC template mass-produced by deep UV lithography. [12,13] This enables the exploitation of high precision lithographically patterned PhC templates in small volume applications, where the simple, material independent, and on demand deposition offered by inkjet printing is used to tailor the device to a more particular application.…”

“…In particular, photonic crystal cavities have the highest finesse of any photonic nanocavity, lending themselves to applications in strong-coupling, [1][2][3] single photon sources, [4,5] low threshold lasers, [6,7] and sensing. [8][9][10][11] Recently, deep UV photolithography has been successfully employed for the fabrication of high quality PhC cavities, [12,13] thus paving the way for their mass production. Concurrently, a few reports have emerged on explored.…”

High-speed polysilicon CMOS photodetector for telecom and datacom

“…On the other hand, polysilicon with grain boundary midgap states has been used for building photodetectors and have achieved comparable or better performance compared to ion-implanted silicon resonant photodetectors without these reliability concerns. [16][17][18][19] Polysilicon detectors at 1280 nm and 1550 nm with a responsivity of 0.2 A/W (at 2.5 V) with 8 GHz bandwidth (at 10 V bias) are already demonstrated in a modified bulk CMOS 17 and have been used to demonstrate the first optical link using monolithic optical transmitters and receivers in a bulk CMOS process. 20 Also, polysilicon exists in the majority of CMOS processes as the gate for FETs, and as is shown in this work, can be used to implement high performance photodetectors without changes to the foundry CMOS processes.…”

“…[12][13][14][15][16][17][18][19] Defects can generate energy states inside the bandgap of silicon and assist absorption of infrared photons. Optical absorption is observed in moderately doped guided-wave silicon devices with pn junctions through the defects generated during ion implantation; 12 and silicon has been intentionally implanted at high dosages (10 13 to 10 14 cm…”

Binary particle swarm optimized 2 × 2 power splitters in a standard foundry silicon photonic platform

“…Incorporating this information into the optimization through lithography simulation [21] can help avoid problematic features. Also, transformations to the device mask to compensate for lithography effects, as in [24], can enable more accurate fabrication when small features are needed.…”